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FMC150 Bypass Filter &amp; DAC Replica

C

Customer

started a topic
over 3 years ago

We are interested in bypassing the DAC output filter to allow the use of the higher Nyquist images. Is this possible using the FMC150? In the future, we would like immigrate to the FMC110. I have already try to bypass the filter using the resistor pads, however we are not able to see the higher replicas that should be produced by the DAC.

4DSP Support

said
over 3 years ago

Hi,

It is indeed possible to bypass the DAC output filter, bit that is not something we allow customers to do by themselves without voiding warranty.4DSP offers a specific order code for the filter bypass. You can contact your sales representative for updating your FMC150 to incorporate the filter bypass.

Best regards,Erik

C

Customer

said
over 3 years ago

that's not what the data sheet states. I wish that was made categorically clear so that all this calling today we wouldn't have had to do to get why we were not getting the image replicas showing up at at later frequencies. One last question, does that mean, this would be the case also for the FMC 110? (we were planning to buy that for our final implementation?) Anyway, thanks at least for the clear up, we know that our premise is correct.

C

Customer

said
over 3 years ago

Just for clarification, the only option to bypass the filter is via modification by 4DSP. In addition, is there is restriction for the FMC110. As we stated, we are concern purchasing the FMC110. Thank you.

4DSP Support

said
over 3 years ago

Hi,

most of our products are designed to not impose any limit on the output and input bandwidth and leave the filtering up to the user. On the FMC150 however the default implementation during assembly is with an output filter on the DAC. We mention in the data sheet that it can be bypassed easily. But we cannot support this as a user changeable feature. It is an ordering option. I am sorry this note in the user manual has caused confusion and we will look at wording it differently.

For the FMC110 we do not have any filtering on the output.

Best regards,Erik

C

Customer

said
over 3 years ago

Erik

Thank you for the clarification about the FMC110. One last question, is there a reference design for the FMC110 for the KC705, similar to the FMC150?

WLT

4DSP Support

said
over 3 years ago

Hi Willie,

the FMC110 can be used on a KC705 but you do need an FMC700 to create a real HPC connector. The KC705 does not connect all the high pin count signals to the FPGA and 4DSP has developed an adapter that uses both the Low pincount and (semi)high pincount connector on the KC705 to create one real High pincount FMC site. Aditionally it adds a cooling fan.